But I gotta *find* the leak before I take any action

Maybe, maybe not.

If you've eliminated all other sources of the leak (plumbing, furnace,
rafters) and given that the unit is 15.5 YO, it might make sense to
start looking for sales and pick up a new unit. It's probably near the
end of it's life anyway.- Hide quoted text -

- Show quoted text -

again if a leak can damage stuff replace the tank, its the likely
problem and well past its expected lifetime..... so even if its not
the cause today tomorrow it can do damage

tanks leak everywhere mine sprayed water out the top of the flue,
around the vent hood. wierdly it didnt put out the pilot, my guess is
the deflector that runs thru the flue happened to direct water away
from the pilot.

i heard water running and was very surprised i had a sprinkler in my
basement..........

in the last 15 years how many vehickes have you purchased? how much
have you spent? why fixate on saving on a hot water tank the new one
will be much more efficent espically when compared to you 15 year old
tank...

foam insulation better over all designs etc etc